Acute renal failure in patients with malnutrition following mitral valve replacement.

A retrospective study of 161 consecutive patients undergoing mitral valve replacement with or without other valve surgery was undertaken to examine the relation between cardiac cachexia and postoperative acute renal failure. The preoperative nutritional state was assessed according to percent of the ideal body weight (W/IW). There were 37 malnourished patients (W/IW less than 0.80) and 124 normally nourished patients (W/IW greater than or equal to 0.80). In nineteen in the malnourished group (51 per cent) and 37 of normal-nourished (28 per cent), postoperative acute renal failure developed. Malnourished patients showed a severe clinical picture preoperatively and complicated operative procedures had to be carried out. To match these clinical factors between the two groups, the observation was limited to the high risk patients who showed severe New York Heart Association Functional Class (III or IV) large cardiothoracic ratio (more than 65 per cent), and long cardio-pulmonary bypass time (exceeding 120 minutes). Even in this subgroup, malnourished patients were susceptible to renal failure (64 per cent versus 20 per cent, malnourished versus normal-nourished respectively). Thus, when malnutrition is superimposed on diminished cardiac performance, acute renal failure may ensue.